I use one of these to hold my tent with sleeping pad wrapped around it. Makes a nice protective package for strapping to my pack. Use another to tame the bulk of a -20 sleeping bag which I use during hunting season. I've put a lot of pressure on that one and it's held up. They come in small mesh bags with a label saying they are guaranteed for life. Even the mesh bags are handy for packing other gear. The cylinder shape compression is unique from other compression sacks on the market and there are situations where that comes in handy. Good product. Wish they had more size options.

Familiarity:
I've put it through the wringer

Purchased this bag knowing full well that synthetic fill bags don't compress very small. Planned on using it with an external frame Kelty pack strapped to the outside. Purchased the Alps "cyclone" compression sack size M to go with it (btw, this is by far the best compression sack I've found, but that's for another review). Given the high loft and generous fit, I was surprised to actually be able to stuff it into the bag compartment of my internal frame pack. Works with mine, but can't guarantee it will fit in yours.

As I said, this bag has a more generous/spacious fit than most mummy bags. Finally a mummy that doesn't make me feel claustrophobic. Once it's had a chance to expand, the bag/loft is fairly thick. Haven't put the temp rating to the test. I've used it almost exclusively Spring, Summer, and Fall. I didn't freeze at 40 or sweat at 65. Did spend one night in it below freezing, but I was wearing a level 7 ECWCS primaloft suit so that doesn't really count.

As of now, I got about 30 nights in this bag and aside from some dirt, it looks brand new. So far it's wearing well. I do store it in a large tupperware so it has plenty of room to breath. Did get the zipper stuck once, but was able to get it undone. The hood and draft collar work pretty good. It zips from both the top and bottom. 3lbs 12oz isn't bad considering the size of this bag and that it's a synthetic fill. Have 20F down bag that is a lb lighter and compresses a good 30% more, but it also cost 5 times as much and takes forever to dry out.

This bag is very good quality for the price. Not for ultralight backpacking obviously, but good for most purposes. I like it so much that I bought the -20F version in XL wide for hunting season, but that one is big enough for 2 of me and weighs a lot more. Not something I would ever pack.

Familiarity:
I've put it through the wringer

This is an updated version of a timeless design and my favorite pack for many situations. I've owned many new good quality internal frame packs, but keep going back to this one.

A back saver for heavier loads and multi-day trips as it effectively distributes the weight to your hips rather than your shoulders. The padding on the lumbar belt and shoulder straps is very good.

These packs are highly adjustable for fit. I'm -5'8" -165lbs -42"chest -30" waist and 18" torso. Even the S/M adjusts out enough to fit me.

Strapping my tent, bag, and pad to the outside leaves 3000 cu in of internal storage which is plenty for me personally. If you need more, step up to the Trekker.

Good organization and access. 6 external pockets, an internal divider, and water bladder compatible. The water bottle pocket on the outside fits my 40oz Klean Kanteen perfectly.

External frames are great for distance hiking, load carrying, and ventilation. That's why many of us still use them. They don't fit as tight as most internal frames, so I still use an internal frame pack for more challenging technical mountaineering.

Yes it's a somewhat old school design, but there's a reason why it's been used for decades.